Field of the Invention
The invention relates to a transport drum in rotary printing presses, having a covering to prevent smearing of a fresh printed product when the printed product is being transported through the press, the covering being secured to the jacket surface of the transport drum and being formed of a carrier material with filamentary support elements secured therein.
From the published German Patent Document DE 14 71 728 B, a guide roller or impression roller having such a covering has become known heretofore, the filamentary support elements thereof extending vertically away from the covering, and being formed of a flexible polyamide. It has been found that these somewhat pointed filamentary support elements can dig into the fresh printing ink and damage the surface thereat. Ink particles can also be removed and deposited disruptively in other regions of the printed image. The embodiment of the support elements in the form of loops, shown as an alternative in this German reference, entails greater production expense, especially if the individual loops are intended to have a like height relative to the jacket surface of the drum.
In another heretofore known version of a covering on a transport drum, as shown in the published European Patent Document EP 0 036 937 B1, a body fabric is used that carries the freshly printed products. In this embodiment, as well, ink absorption by the covering cannot be precluded, so that it is necessary to clean the covering at given intervals of time. If the cleaning is performed in the printing press, the rubbed-off ink residues may then soil other press parts and cause printing problems.
Proceeding from this state of the prior art, it is an object of the invention of the instant application to provide a transport drum in rotary printing presses which is of such construction as largely to prevent smearing or deposition of ink particles on the support elements of the covering, so as to avert impairment of a freshly printed image on a printed product.